The invention relates detection probes for in depth resolving optical spectroscopy and spectrometry.
Various possibilities for detecting the light scattered in tissue in dependence on the distance from the source of illumination already exist. Apart from the use of photodetector arrays directly on the tissue surface, there is the possibility of transmitting the light to the detectors by an arrangement of light guides.
U.S. Pat. No. 4,321,930 discloses an apparatus for monitoring metabolisms in bodies, in which a probe which contains a plurality of deflecting devices, to be specific bent light guides, is placed on the skin.
A corresponding device is also known from DE-A-25 17 129, as a photoelectric pulse pick-up with fiber optics.
In a known configuration, as represented in FIG. 1 and described in EP 771 546 A2, optical fibers in a certain arrangement, which determines the depth of detection and the in-depth resolution, can be placed on the tissue in abutting manner. At the same time, the fibers (illumination fiber 1, detection fibers 2) are cemented into a corresponding fiber holder 3 (material: e.g. PEEK, high-grade steel) or fixed in relation to one another at previously defined spacings by a casting compound (e.g. epoxy casting compound Epo-Tek 301-2). For reasons of biocompatibility, corresponding materials must be used. Also shown in FIG. 1 is the tissue 4, into which light is coupled from the fiber 1, and the paths 5 of the scattered light, which is picked up by the individual detection fibers 2. Because of the relatively unfavorable leverage, such a detection probe must have a wide base plate to allow it to be fixed securely. The use of more than three fibers 1, 2 makes the feeding-in fiber optic cable quite rigid, resulting in great bending radii and consequently a great space requirement.
The direct coupling of the scattered light into the fiber makes the known arrangement very effective. However, this is at the expense of convenient handling and fixing. With this type of optical detection, a fiber diameter beginning from 50 xcexcm is adequate in the case of a fiber spacing of 0.3 mm.
Against this background, it is an object of the invention to reduce the overall size of the detection probe and improve handling.
A detection probe with the features of claim 1 is proposed to achieve this object. Configurations of the invention are the subject of subclaims.
An orthogonal detection of the scattered light is preferably provided, with a fiber guided parallel to the tissue surface and with a deflection of the light of between 0xc2x0 and 180xc2x0, preferably by 90xc2x0, with at least one mirror surface.
The invention allows the detection probes to be made especially flat, thereby reducing the overall size and improving handling. Electrodes can be easily fixed, in a way similar to the electrodes in the case of an electrocardiogram, and are also not felt to be a hindrance, since thexe2x80x9cleadsxe2x80x9d lie flat against the body and do not protrude perpendicularly from it.
Further aims, advantages, features and application possibilities of the present invention emerge from the following description of an exemplary embodiment on the basis of the drawing. All the features described and/or graphically presented here form the subject-matter of the present invention in themselves or in any desired meaningful combination, even independently of how they are combined in the claims or the way in which the latter relate back to one another.